An extremely small dosimeter (SOF dosimeter) combining a scintillator and an optical fiber has been developed as a dosimeter that can be inserted into a human body and has excellent real-time responsiveness. Such an SOF has been developed as a dosimetric device for brachytherapy using Ir-192, but it is also applicable to X-ray dosimetry.
However, diagnostic X-rays are relatively low in energy as compared with γ-rays for therapy, and energy sensitivity dependence at a tube voltage in a range of 40 kV to 150 kV is not considered.